There are a variety of methods for producing toner. One of the methods is called a pulverizing method. According to the pulverizing method, toner is produced by pulverizing raw particles into smaller particles. The toner produced by the pulverizing method tends to include larger amount of colorant particles that are not covered with or covered very little by binder resin particles and resin particles not including the colorant particle. Such toner may cause toner scattering.
Another method is called an aggregating method. According to the aggregating method, toner is produced by aggregating colorant particles with binder resin particles in a liquid. To produce toner including smaller amount of colorant particles that are not covered with or covered very little by binder resin particles and resin particles not including the colorant particle, using the aggregating method, the toner particles may become larger. Larger toner particles may degrade quality of an image, because the toner particles may not be properly aligned on a surface of a sheet.
The size of the toner particles may be reduced by adjusting zeta-potentials of the colorant particles and the binder resin particles in the aggregating method. However, toner produced by this method may include larger amount of resin particles not including the colorant particle (homo-particles). When an image is formed with toner containing many homo-particles, the toner may not have sufficient coloring property and filming of the toner may occur.